Counterbalance mechanism



E. E. FOSTER 2,453,424

COUNTERBALANCE MECHANISM Z-Sheets-Sheet 1 Nev; 9, 1948.

Filed Jan. 6, 1947 0 Q E Fade/F. W WQ Nov. 9, 1948. F R 2,453,424

COUNTERBALANCE MECHANISM Filed-Jan. 6, 1947 2 Sheets-Sheet? Edwin E. Easter and i' atented Nov. 9, i948 UNITED STATES PATENT OFFICE COUNTERBALANCE MECHANISM Edwin Foster, Austin, Tex. Application January 6, 1947, Serial No. 720,352

This-invention relates to a window or door counterbalance mechanism of the type arranged at the top of the window or door frame, and operative by coiling or uncoiling a spring.

It is, therefore, an object of the invention to provide positive means to shift the counterbalance mechanism as the'window israised or lowered. Another object resides in the provision of a screw and nut device on a shaft/to pwitively shift the mechanism as the Window is raised or lowered.

A further object resides in the provision of a shaft having a coiled spring thereon to act as counterbalance means, andscrew threaded means on the shaft to shift the latter for the purpose of maintaining the cords or cables connected to the window in vertical alignment.

Further objects will be apparent from the following description, when considered in connec tion with the accompanying drawing in which? Figure 1 is a front elevation of the counterbaldowframe,

i Fig. 2 is aplanview of the mechanism on a large scale with certain parts in section,

Fig. 3 is aperspective view of one of the supportin brackets,

ance mechanism applied to a windowfand winbers,

Fig. 5 is an endview of the bearing of Fig. 4,

Fig. 6 is a side View of an anchoror bearing device.

The invention is illustrated as applied to a window, but the invention may also beapplied to a, door orany otheropening and closing memher which is to be counterbalanced, such as a screen, etc, Thewindow frame I may be constructed of wood or metal having relatively narrow vertical members 8 and a top member 9. As a double sash window with two sliding frames, Fig. 1 shows the upper sash illhaving a glass pane H. Any means may be employed to retain the window sashes in the frame, such as the well known side strips along the vertical and horizontal parts of the window frame.

The counterbalance mechanism is applied on: the upper or top frame member 9, and is supported on two supporting brackets l2, each having two partial slots [land 15 therein for the upper and lower sashes. Each bracket 12 is suitably held in place on the frame member 9 by means of screws i6 which pass through holes ll in the right angle brackets. Each bracket i2 has a base portion 18., in which the screw holes.

Fig. 4 is a side view of one of the bearing mem 10Claims. (Cl. 16-198) I! are provided, and a right angle portion I9 in which the slots Hi and [5 are provided, slots 14 for one window pane, andlS for the other pane. A shaft 20 is rotatably supported in the brackets having a bearing 2| preferably of brass at the 29 thereon. Adjacent the pulley 21 there is prov vided a screwthreaded sleeve 30 on the shaft 20- and having screwthreads 3| and secured to the shaft 20 by means of a pin 32. screwthreads 3! of the sleeve 30mesh with the internal threads23 of the bearing nut 22. There is also provided on the shaft 20 a retaining and adjustment sleeve 33 having a section 34, two or more such as four radial holes 35in a section 44 and a section 36 with longitudinal perforations or; slots 45 therein through which a cotter pin 31 or the like may extend through the section and through a hole in the shaft, as shown in Fig; -2. A right hand wound spiral spring 38 is secured on the sleeve sections 34 and 26.

The window sash i0 is connectecl to the counterbalance device by means of cables 39 secured at one end 40 to the window frame by means of a screw 4! and the other end to its respective pul ley such as by means of a screw 42 bearing against a cotter pin 43 as shown in Fig. 2.

. As shown in Fig. 2, the shaft 20 is free to turn in the sleeve 26 and bearing 2 5, whereas the sleeve 33, 34 rotates with the shaft. Also, the cone pulleys 2'Iand 28 rotate with the shaft 25.

The operation of the device is as follows:

As the sash I0 is moved downward, the cables 39 will cause the cone spiral 29 to turn and wind up the spring 33. As the sash is lowered, the cones 21 and 28 move to the left, duetothe fact that the threaded sleeve 30 operates as a screw in the stationary nut or bearing 22. Since the screw 30 is provided with the same number of threads per inch as the cone 21, the cables 39 will remain in a vertical plane and will not crawl from one side to the other.. The spring 38 isloosely wound, that is, the coils are not jambed together,

but preferably have a short space between each coil. Then as the spring winds, it may compress slightly or stretch slightly to adjust itself to the perfect alignment determined by the screw thread The external} has lessfrictic'n when the coils are not touching each other.

In order to assemble this device, the spring is completely freethat is, in its normal, unwound position, and the pin 3'! is out of the hole in the shaft 20. The sash is placed in the window at its bottom position and the cables 39, are extended down through the holes in the frame, and attached to the sash by means of the nails .orscrews ii. The brackets i8 and I9 are identical and are positioned and fastened to the top window frame 9. The winding nut 44 is then wound by means of two nails fitting in the holes 35 until the spring is sufiicientlystrong to lif-tthe sash. The pin 31 is then inserted through the slots 45 and the hole in the shaft 20. The number of turns can be counted and a chart made to correspond to a certain weight sash. Also, calibrations canbe made on the edge of the slots 45 to line up with the pin 3! to indicate the approximate position to whichit should be wound. I

It is thus apparent that as the sash is moved up and down, the shaft is shifted longitudinally, due to the screw threads 3! on the sleeve 30, and thus the cables 39 will always be maintained in a vertical position. Also, the coneshaped pulleys 2i and 28 willcompensatefor the slight change in the tension in the spring as the leverage changes onv the spiral track of the cones.

It will be noted that the coils of the spring 20 are shown in spaced relation, rather than in contact with each other, and this is preferable,

since the spring acts when it is twisted, Thus, the spring is provided with an initial tension in,v

the relatively unwound position when the sash isclosed. In a springwith the .coils touching each other, such springs are made with a longitudinal tension as well as a circular tension, when,

the spring is coiled, resulting inconsiderable friction, due to the sides of the coils rubbing on frame, a pair of bearings for the shaft mounted,

in a stationary relationship in each bracket, and means on the shaft at at least one bearingto shift the shaft when the window is raised or lowered.

2. A counterbalance mechanism'for-windows and the like comprising a shaft having a pulley:

at each end, a bracket on each side of awindow frame, agpair of bearings for the shaft mounted:

ina stationary relationship in each bracket, and.

a'threaded sleeve secured on the shaft at at least one bearing to shift the shaft when the window is raised or lowered.

3. A counterbalance mechanism for windows.

andthe like comprising'a shaft having a pulley at each end, a bracket on each side of a window frame, a .pair of bearings for. the shaftmounted in a stationary relationship in each bracket, means on the shaft at at least one bearing to shift the shaft when the window is raised or lowered, and a spring secured at one end to the shaft, and the other end to the other bearing to counterbalance the window sash.

l. A counterbalance mechanism for windows and the like comprising a shaft having a pulley at eachend, a bracket on each side of a window frame, a pairof' bearings; for the shaft mounted in a stationary" relationship in each bracket, means on the shaft at at least one bearing to shift the shaft when the window is raised or lowered, and a spring secured at one end to the shaft, and the other end to the other bearing to counterbalance the window sash, said spring having a plurality of coils which are spaced from each other.

5 .LA1 counterbalance mechanism for windows and the like comprising a pair of brackets mounted in spaced relation on the topof. a. window frame, a, bearing member mounted in a. station? ary manner in each bracket, one bearing having a sleeve extension, a. sleeve mountedin the other. bearing in threaded relationship therewith, a shaft rotatably mounted in the. bearing with the sleeve extension and: in the threaded sleeve by a pin connection, an adjustable sleeve mounted onthe shaft to rotate therewith, and having an, ex tension thereon, a coil on the shaft connected atone end to the adjustable sleeve, and the other end on the sleeve. extension, and a pulley on each end of the shaft, each connected by a cable to a. sash of the Window, movement of the window causing a rotation of the pulleys and shaft and the, screwthreaded, connection of the threaded bearing and its threaded sleeve causing. a lateral.

shifting of the shaft and pulleys.

6. A counterbalance, mechanism for windows and. the like-comprising a pair of bracketsmounted in. spaced relation on the top of a window frame, a bearing member mounted ina stationary manner in each bracket, one bearinghaving a sleeve extension, a sleeve mounted in the other bearing in, threaded relationship therewith, a

shaft rotatably mounted in the bearing with the sleeve extension and in the threaded sleeve by a pin connection, an adjustable sleeve mounted'on the shaft to rotate therewith, and having an extension thereon, a coil on the. shaft connected at one end to the adjustable sleeve and the othen end onthe sleeve extension, a pulley on each end of the shaft, each connected by a cable to asash.

of the window, movement of the window causing a, rotation; of the pulleys and shaft, and: the: screwthreaded connection of the threaded bear'- ing and its threaded sleeve causing a lateral. shifting of the shaft and pulleys, and means.- for. adjusting and locking the: adjustable sleeve on the shaft.

7. A- counterbalance mechanism for: windows; and the like comprisinga pairqof brackets: mount.- ed in spaced relation on the top, of a windowframe; a bearing: member mounted in a stationary manner in. each bracket; one bearingsh'aving a sleeve extension, a sleeve mounted inthe other bearing in threaded relationship therewith, a

shaft rotatably: mounted in the bearingwith the.

sleeve extension and in the threaded sleeve by a pin: connection, anad 'ustable sl'eevemounted on theshaft to rotate therewith, and having an extension thereon, a coil on the shaftconnected' atone endttotheadjustable sleeve, and the otherend onthe-sleeve extension, a pulley oneach end of. the shaft, each. connected by a cablev to a sash of the window, movement of the window causing a rotation of the pulleys and shaft and the screwthreaded connection of the threaded bearing and its threaded sleeve causing a lateral shifting of the shaft and pulleys, and means for adjusting and locking the adjustable sleeve on the shaft, the coils of the spring being in spaced relation relative to adjacent coils.

8. In a counterbalance mechanism for windows and the like having a coil spring mounted on a rotatable shaft with a pulley at each end connected to a window sash, positive means for shifting the shaft and pulleys axially as the window sash is raised and lowered.

9. In a counterbalance mechanism for windows and the like having a coil spring mounted on a rotatable shaft with a, conical pulley at each end connected by a cable to a window sash, positive means including a screwthreaded connection for shifting the shaft and pulleys axially as the window sash is raised and lowered.

10. In a counterbalance mechanism for windows and the like having a coil spring mounted on a rotatable shaft with a conical pulley at each end connected by a cable to a window sash, positive means including a screwthreaded connection for shifting the shaft and pulleys axially as the window sash is raised and lowered, said means including an externally threaded sleeve secured on the shaft and an internally threaded bearing nut secured on a bracket with the threaded portions cooperating with each other toshift the shaft.

EDWIN E. FOSTER.

N 0 references cited. 

